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    <title>Document</title>
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    <script>

        // 1. Symbol.hasInstance
        class Person {
            static [Symbol.hasInstance](params) {
                console.log('Person - params: ', params);
                // return true;
            }
        }
        let obj = {name: 'js'}
        console.log(obj instanceof Person);


        // 2. Symbol.isConcatSpreadable
        let arr1 = [1, 2, 3];
        let arr2 = [4, 5, 6];
        arr2[Symbol.isConcatSpreadable] = false;
        console.log(arr1.concat(arr2));
    </script>
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